A total concentration fixed-grid method for wet chemical etching process
Date of Issue2007
School of Mechanical and Aerospace Engineering
Chemical Etching (CE) is an important production process for the fabrication of electronic devices. CE process is widely applicable in the manufacturing of integrated circuit (IC) devices, micro-electro-mechanical-system (MEMS) devices, production of shadow mask for color TV etc. Wet chemical etching (WCE) is widely used CE process due to its low cost, high etch rate and good selectivity compared to other existing CE processes. WCE process involves dissolution of substrate by chemical reaction with liquid chemicals called as etchant. The substrate to be etched is partly protected by photoresist mask to protect it from direct contact with the etchant. The mask forms the desired pattern over the substrate surface. During the process of etching, the etched interface moves because of the dissolution of substrate by the etchant. Hence, this process is regarded as a moving boundary problem. Because of the presence of mask, the etched interface takes a very complicated shape in multidimensional etching. Predicting and understanding the etching profile growth is therefore very useful in designing the pattern structure used in fabricating IC and MEMS devices. The presence of moving boundary makes the problem highly non-linear.